The ”rules” of biodiversity
Usually the word ’naturally’ is not one you would connect with cities, but in fact, the exact same rules apply for the distribution of animals and plants in the cities as in the ‘wild’ nature. It is the surrounding environment and habitats, which determine the distribution of species.
The five main rules are:
Variation
The variation in the physical conditions is one of the most important aspects when talking about furthering biodiversity. The more varied the physical conditions are (grass, tree, water, soil, slopes, rocks, salt, structures, etc.), the more species can potentially live there. Each species has its own niche, so the more niches you create by creating a greater variety in the physical conditions, the more species can live in the area.
Food for all
It is also important to have variation in the biological conditions (grass, carcasses, hay, dead trees, flowers, etc.), because you thereby ‘serve’ several different types of food. This again increases the amount of species, which are able to live in the area.
Large areas
The larger the area is, the more species it can hold. A large area can contain a much bigger variation than a smaller area, and it will generally provide more space for animals and plants.
Take the time
Continuity in time is one of the most important issues when talking about biodiversity. The longer an area has had to develop and create variation, the more species are typically found. It will usually take quite some time before the different species’ living conditions emerge in the various locations. Furthermore, older areas will, with time, have gathered more and more species from the surroundings.
Let go
Do let the areas take care of themselves. Nature always has its own ideas, which create new and more living areas – ideas, we would never even think of.
In the city, it is important to remember that many species have a hard time spreading to new areas. Imagine two parks with 600 meters of housing in between them. This is the equivalent to two islands separated by the sea. Exactly how difficult it is for the species is highly dependable on the species themselves. For birds, this is a fairly easy task – just like for insects and plants, which are carried off by the wind. However, amphibians, reptiles, earth-living insects and plants, which are not spread by the wind, find it very difficult.
This is the reason why it is crucial to create green corridors that help the species to spread between the suitable living areas. Or that you yourself – either consciously or un-consciously – help the species move. Many plants are spread by birds or mammals when they are caught in the fur or by being eaten and eventually reappearing again.
But remember, just because there are many species in an area and thus a high biodiversity, it does not mean that it is important to prioritise the area when speaking in pure management terms. Nature management is about preserving the areas, which hold a special mix of species or where the individual species are rare.